1. Field of the Invention
The present invention relates to a liquid dispensing pump for dispensing a liquid stored inside a liquid container from a nozzle head by pressing down the nozzle head.
2. Description of the Related Art
Conventional liquid dispensing pumps possess a nozzle head for dispensing a liquid, a liquid container for accumulating and storing the liquid, a cylinder located over the liquid container, an inlet valve for bringing the liquid stored in the liquid container into the cylinder with the ascending motion of the piston and an outlet valve mechanism for bringing the liquid brought into the cylinder out to a nozzle head with the descending motion of the piston.
In these conventional liquid dispensing pumps metal coil springs have been used as a means for increasing momentum to raise the cylinder after releasing the downward pressure applied to the nozzle head to lower the cylinder. These coil springs are normally provided at a position where they can contact a liquid posing a risk of metal spring corrosion. When these liquid dispensing pumps are used in the field of cosmetics, the possibility that a metal constituent may elute into a cosmetic makes such design hygienically undesirable.
Moreover, these liquid dispensing pumps are normally manufactured by molding a resin. When disposing of these liquid dispensing pumps, due to difficulty in dismantling metal coil springs, it becomes impossible to recycle the pumps.
To solve these problems, a resin coil spring may be used. However, the use of the resin coil spring makes it impossible to obtain necessary momentum for making the liquid dispensing pump function properly.
The present invention describes a liquid dispensing pump, which can effectively prevent a coil spring from corroding and eluting into the liquid while providing a necessary momentum for proper pump function by using a strong metal coil spring.
In an embodiment, the present invention provides a liquid dispensing pump adapted to be connected to a container, comprising: (A) a nozzle head having a nozzle from which a liquid stored in the container is dispensed; (B) an inner tube connected to the nozzle, said tube having (i) a closed end on a side opposite to the nozzle, (ii) a first outward projection at the closed end, (iii) a second outward projection apart from the closed end, and (iv) an opening between the first and second outward projections; (C) a cylinder into which the closed end of the tube is inserted; (D) a piston provided inside the cylinder and movable between the first and second outward projections, said piston being liquid-tightly slidable along an inner wall of the cylinder, wherein (a) when the nozzle head is not pressed downward, the first outward projection liquid-tightly contacts the piston, and (b) when the nozzle head is pressed downward, the first outward projection is detached from the piston to communicate the tube and the cylinder between the first outward projection and the piston through the opening of the tube, whereas the second outward projection pushes the piston downward; (E) a pushing member which constantly pushes the nozzle head upward; and (F) a one-way valve provided at an end of the cylinder opposite to the nozzle head, said valve opening only in a direction to bring a liquid stored in the container into the cylinder; wherein (I) the liquid in the container moves into the cylinder though the valve when the nozzle head moves upward by the pushing member, and (II) the liquid brought in the cylinder moves between the first outward projection and the piston into the tube through the opening of the tube toward the nozzle when the nozzle head is pressed downward.
Any suitable structures and members can be used to constitute the above structures. For example, in an embodiment, the end of the cylinder is tapered, and the valve has a tapered surface to liquid-tightly contact the tapered end of the cylinder when the nozzle head is pressed downward. In another embodiment, the end of the cylinder is tapered, and the valve includes an O-ring to liquid-tightly contact the tapered end of the cylinder when the nozzle head is pressed downward. In still another embodiment, the end of the cylinder has an opening, and the valve includes a ball and a spring pressing the ball downward to liquid-tightly close the opening when the nozzle head is pressed downward, said spring being attached to the closed end of the tube.
Further, in an embodiment, the first outward projection is an O-ring which liquid-tightly contacts the piston when the nozzle head is not pressed. In an embodiment, the second outward projection is an O-ring which liquid-tightly contacts the piston when the nozzle head is pressed.
The liquid dispensing pump may further comprise an upper valve provided at a connection between the nozzle head and the tube, wherein said upper valve opens when the nozzle head is pressed. In the above, in an embodiment, the upper valve includes an O-ring to liquid-tightly close the connection between the nozzle head and the tube when the nozzle head is not pressed downward. In another embodiment, the upper valve includes a ball and a spring pressing the ball upward to liquid-tightly close the connection between the nozzle head and the tube when the nozzle is not pressed downward.
Additionally, the pushing member may be a spring provided along a periphery of the tube.
The present invention can equally be applied to a container with a liquid dispensing pump, which comprises: the liquid dispensing pump described above (with any combination of embodiments); and a container attached to the liquid dispensing pump. Any suitable structures and members can be used to constitute the above structures. For example, the container may be cylindrical.
In the above, in an embodiment, the container has a movable bottom which is liquid-tightly slidable upward along an inner wall of the container according to the pressure in the container, wherein as a liquid is stored in the container and the liquid is dispensed through the nozzle, the movable bottom moves upward. Preferably, the movable bottom is formed in a shape corresponding to the shape of the end of the cylinder of the liquid dispensing pump. The liquid dispensing pump can be liquid-tightly attached to a top of the container.
In another aspect of the present invention, provided is a liquid dispensing pump for dispensing a liquid stored and accumulated inside a liquid-storing unit from a nozzle head by pressing down said nozzle head provided over the liquid-storing unit. The pump comprises: (i) a cylinder provided on top of said liquid-storing unit, (ii) a piston that can move reciprocally inside said cylinder, (iii) a coupling tube for lowering said piston by transmitting pressure applied to said nozzle head by connecting said nozzle head with said piston, (iv) a coil spring provided at the peripheral portion of said coupling tubes for increasing momentum of said piston via said coupling tubes in its ascending direction, (v) an inlet valve for bringing a liquid stored in said liquid-storing unit into said cylinder with the ascending motion of said piston, (vi) and an outlet valve mechanism for moving the liquid brought into said cylinder with the descending motion of said piston out to said nozzle head via inside said coupling tube.
In the above, the inlet valve need not but may be provided near the lower end of said cylinder comprising the first valve mechanism that blocks an opening formed near the lower end of said cylinder, said opening being a passage between said liquid-storing unit and said cylinder, when inside said cylinder is pressurized, and unblocks said opening when inside said cylinder is decompressed. Further, the internal surface of the lower end of said cylinder need not but may be formed in a tapered shape, and said first valve mechanism has a tapered valve body so that its external surface can closely contact the internal surface of the lower end of said cylinder. The first valve mechanism need not but may have a supporting component which can move up and down and an O-ring provided at the periphery of said supporting component. Also, the outlet valve mechanism need not but may comprise the second valve mechanism which opens an opening, said opening being a passage between inside said coupling tube and inside said cylinder, by separating from said piston when said nozzle head is pressed down, and blocks said opening by closely contacting said piston when the pressure applied to said nozzle head is released. In the above, the piston may comprise packings made of resin.
Further, the outlet valve mechanism need not but may be provided near the lower end of said coupling tubes comprising the second valve mechanism that unblocks an opening formed near the lower end of said coupling tubes, said opening being a passage between inside said cylinder and inside said coupling tubes when said nozzle head is pressed down, and blocks said opening when the pressure applied to said nozzle head is released. Alternatively, the outlet valve mechanism may be provided near the upper end of said coupling tubes comprising the second valve mechanism, which unblocks an opening formed near the upper end of said coupling tubes, said opening being a passage between inside said coupling tubes and inside said nozzle head, when said nozzle head is pressed down, and blocks said opening when the pressure applied to said nozzle head is released. In the above, in an embodiment, by being pressed down by said nozzle head from its upper position, the second valve mechanism unblocks the opening formed near the upper end of said coupling tubes, said opening being a passage between inside said coupling tubes and said nozzle head. Further, the second valve mechanism may be provided inside said nozzle head. Additionally, the second valve mechanism may have a supporting component which can move up and down and an O-ring provided at the periphery of said supporting component. Also, in an embodiment, by using the momentum of said coil spring, the second valve mechanism blocks the opening formed near the upper end of said coupling tubes, said opening being the passage between inside said coupling tubes and said nozzle head. In another embodiment, an outlet valve mechanism is provided near the lower end of said coupling tubes comprising the third valve mechanism that unblocks an opening formed near the lower end of said coupling tubes, said opening being a passage between inside said cylinder and inside said coupling tubes when said nozzle head is pressed down, and blocks said opening when the pressure applied to said nozzle head is released. Additionally, the liquid-storing unit may comprise a hard cylinder component and a piston component which moves inside said cylinder component in the direction of said nozzle head as the amount of the liquid decreases.
For purposes of summarizing the invention and the advantages achieved over the prior art, certain objects and advantages of the invention have been described above. Of course, it is to be understood that not necessarily all such objects or advantages may be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein.
Further aspects, features and advantages of this invention will become apparent from the detailed description of the preferred embodiments which follow.